Structure, Phase Composition and Mechanical Properties for the High-Entropy Solid Solutions Based on MnFeCoNiCu System Versus Collective Behaviour of Their Constituents

Structure and phase-composition changes of the cast multicomponent alloys based on MnFeCoNiCu are studied depending on variations in the enthalpy and entropy of mixing, the difference in atomic sizes, and the concentration of valence electrons, starting from the medium-entropy TiFeCoNi alloy and approaching the Cantor alloy. Changes in the crystal structure from h.c.p. to f.c.c. one as well as variations in the phase composition are revealed. As shown, the specified changes lead to significant strengthening with significant plasticity. Such plasticity is caused by the f.c.c.–h.c.p. martensitic transformation, which is combined with the plastic deformation of the distorted lattice, which, in its own turn, is characterized by significant strengthening.